Organic detergents for lubricating oil



Patented Mare 3,, 1945 2,311,333 v oaoamo namesake roa wamcarmo Fulton L. Johnston, East Alton, m, assignor io Shell Development Company, San Francisco, Calm, a corporation of California 7 No Drawing. Application October 19, 1942, Serial No. 462.618

Claims.

This invention relates to non-corrosive compounded mineral lubricating oils and more perticularly deals with lubricating oils containing non-corrosive oil-soluble organic detergents which possess the property of softening carbon, preventing or retarding sticking of piston rings and deposition of lacquer in internal combustion engines when these engines for long periods of time under severe conditions 0! loading.

It is known that in modern internal combustion engines, such as aviation gasoline engines operating at relatively high temperatures due to their high power output, or in high-speed Diesel engines due to incomplete combustion, piston rings have a tendency to become stuck in the grooves. Lacquer and/or carbon formation appear to be the principal reasons for this occurrence.

Moreover, scumng or top lands due to the formation of hard carbon particularly when using Iii groups; cyclohexyl, methyl cycloheizyl and other alkyl cyclohexyl and dind poly-alicyclic radicals, such as may be obtained by hydrogenation of alkyl phenols, alkyl naphthols, or of cyclic polymerization products of acetone, methyl ethyl ketone, mesltyl oxide, etc.; phenyl, naphthyl and their alkyl derivatives, such as methyl phenyl. ethyl phenyl, methyl naphthyl, etc. The hydrocarbon radicals may'contain a polar substitution group, preferably not more than one, oi

high thermal stability, in particular, hydroxyl,

carboxyl ester, ether, thio-ether, chlorine and 'nitro radicals, as well as nitrogen in heterocyclic aromatic ring structures such as in pyridine, quinoline, etc. Radicals of lesser, stability such as aliphatic amino, imino, hydrosulilde, etc., radicals are less desirable.

high viscosity index oils may cause serious dam I sue to the engine.

. To eliminate or reduce the lacquer deposition,

ring-sticking, and hard carbon forming char-' acteristics of oils it is necessary to compound them with additives normally metal soaps which improve the oils in one or more of its proper= ties Now, I have iound purely organic compounds of excellent solubility in lubricating oils is attached dlrectlyto four other carbon atoms.

Alcohols containing such a nee-carbon atom are represented by the formula: V

(cmhois Rc-(crm,on I

A csmon wherein I, 1!, and .2 are whole numbers preferably l, and the R. radical is a hydrocarbon radical which may be aliphatic, alicyclic, aromatic or heterocyclic, examples being methyl, ethyl, propy 3 9N99 butyl, amyl, hexyl which are both detergents and carbon softeners.

' The preferred type of alcohol is one in which- .r, y, and z are 1 and the R group is a carbinoi group as in penta-erythritol, the latter having the formula C(CHzQHM. Symmetrical alcohols having short, equal length carbon chains linking hydroxyl radicals to the neo-carbon atom appear to he the most efiective carbon softeners.

These alcohols may be prepared by reacting hydrocarbon trihalogens of the general formula R-C-Hahwith hydrogen or a metal-cyanide, e; g. silver, potassium, etc. cyanide to form the nitrile R-C-(CEN) hydrogenating the nitrile to the amine and converting the amine to the corresponding alcohol by treating the iormer V with nitrous acid. Some alcohols, especially normally insoluble penta-erythritol and o-tertiary-trlhydroxy butyl pyridine are readily and cheaply prepared by the specific reaction 0! acetaldehyde or o-methyl pyridine, respectively, with formaldehyde. This not applicable generally.

Poly-hydroxy alcohols 01 the above types are in mineral oils. It is therefore necessary to esteriiy at least some and preterably all 0! the hydroxy groups with mono carboxylic acids of sumcient carbon atoms to impart solubility. Acids suitable ior esieriiying these alcohols are carboxylic acids having 8 or more carbon atoms per molecule, and preferably between 12 and 24 carbon atoms. These acids may be saturated or unsaturated aliphatic .or' cycle-- aliphatic mono carboxylic acids preferably having not more than one oleflnic double bond such almitic,

as iatty acids. e. g. lauric, myristlc, stearic, arachidic, behenic, oleic, erucic acids, etc., higher petroleum naphthenic acids; aromatic acids, such as phenyl stearic alkyl pyridine carboxylic acids, etc.

and higher alkyl I! Saturated carboxylic acids, in-general. are prealkyl benzoic, allql phenyl acetic,

ferred. If desired these acids may contain chlorine or 'bromine preferably in a position other than in alpha position to the carboxyl radical.

Some specific examples of esters derived from the above-mentioned alcohols and acids are enta-erythritol trland tetra-laurate, palmitate, stearate, oleate, naphthenate, phenyl stearate, etc., 2-methyl-2-methylol-1, 3-propanediol dior tri-palmitate, oleate, naphthenate, phenyl acetate, phenyl stearate; benzo trimethylol diand tri-stearate, oleate, naphthenate, isopropyl benzoate, phenyl stearate, etc., corresponding esters of 3-methyl-2,2-dimpthylol-1- .butanol, 2 amino-2-methylol-1,3-propanediol,

2,2-dimethylol-3-hydroxy n-propyl benzene, benzo trimethylol, o-tertiary-tri-hydroxy butyl pyridine, etc.

Suitable amounts of organic detergent ester which an anti-ring-sticking and soft carbon forming oil should contain range from about to 10.0% andpreferably from .'75% to 5.0%.

The above organic addition agents may be combined with other detergents, e. g. oil-soluble metal'salts of carboxylic and sulfonic acids, such as soaps of fatty acids, chlorinated fatty acids, aromatic' fatty acids, alpha aromatic amino monocarboxylic acids, naphthenic acids, rosin acids, mahogany acids. Salts of polyvalent metals are, in general, most active, e. g. Mg, Ca,

Sr, Ba, Zn, Cd, Al, Sn, Sb, Cr, Mn, Co, Ni, etc.

crankcase lubricating oils containing the esters of the instant invention may contain additional compounding ingredients such as oxidation inhibitors, pour point depressors, blooming agents, extreme pressure compounds, anti-sludging agents, etc.

The following example further illustrates my invention:

Example An SAE-SO grade refined West Texas lubricating-oil was divided. into 4 portions. To one portion was added 2% by weight of p'enta-erythritol tetra-stearate. To a second portion was added 2% by weight of a mixed naphthenic and stearic tri-ester of o-tertiary-trihydroxy-butyl pyridine.

To a third portion was added 2% by weight of di-cetyl-phthalate The doped and undoped oils were tested individually in a Fairbanks-' Morse Diesel engine having a four-stroke cycle operating at 900 R. P. M. with the lubricating oil temperature of 151-10 F. The duration of the .test was 40 hours.

Examination of the pistons as they were i'emoved from the engine after the runs showed that the oil alone gave a piston that had a medium coating of lacquer and a somewhat abrasive carbon deposit which had most of the. piston rings stuck tight in the grooves. Oil containing di-cetyl-phthalate gave'pistons in practically the rate.

having a neo-carbon atom, said carboxylic acid having a minimum of 8 carbon atoms and having not more than one oleflnic double bond.

2. The composition of claim 1 in which the ester content is from about 25% to 10%.

3. The composition of claim 1 in which the ester content is from about .75% to 5.0%.

'4. A compounded mineral lubricating oil containing dissolved a small amount sufficient to carbon arccar on.

onmon wherein R is a hydrocarbon radical and :z y, and z are whole numbers not less than 1, said carboxylic acid having a minimum of 8 carbon atoms and having not more than one oleflnic double bond.

6. A compounded mineral lubricating oil suitable for internal combustion engines containing dissolved a small amount sufficient to retard piston of an oil-soluble saturated'mono-carboxylic acid ester of penta-erythritol, said carboxylic acid having a minimum of 8 carbon atoms and having not more than one oleflnic double bond.

7. A compounded mineral lubricating oil suitable for internal combustion engines containing dissolved a small amount suflicient to retard piston ring sticking of an oil-soluble fatty acid ester of an alcohol selected from the group consisting of tri and tetra hydroxy alcohols having a neo-carbon atom, said fatty acid having from 12 to 24 carbon atoms and having not more than one oleflnic double bond.

8. A compounded mineral lubricating oil suit able for internal combustion engines containing dissolved a small amount, suflicient to retard piston ring sticking of an oil-soluble penta-erythritol stearate.

9. A compounded mineral lubricating oil suitable for internal combustion engines containing dissolved a small amount sufllclent to retard pistln ring sticking of penta-erythritol tetra-stea 10. The composition of claim 5 wherein the hydr'ocarbon radical R contains a polar substitution radical selected from the group consisting of OH, COOR', OR', SR', --Cl, NO2, and --N= in heterocyclic aromatic ring structure, R being a hydrocarbon radical.

11. A compounded mineral lubricating oil suitable for internal combustion engines containing dissolved a small amount suflicient to retard piston ring sticking ofan oil-soluble mono-carboxylic acid ester of o-tertiary trihydroxy butyl pyridine, said carboxylic acid having a minimum of 8 carbonatoms and having not more than one oleflnic double bond.

12. A compounded mineral lubricating oil containing dissolved a small amount sufllcient to retard piston ring sticking of an oil-soluble mono- R-C-CHQOH CHzOH wherein R isa radical selected from the group comprising hydrocarbon radicals and hydrocarbon radicals containing a polar substitution radical of high thermal stabiilty, said carboxylic acid having a minimum of 8 carbon atoms and having not more than one olefinic double bond.

13. A compounded mineral lubricating oil containing dissolved a small amount sufiicient to' retard piston ring sticking of an oil-soluble monocarbomlic acid ester of an alcohol having a neocarbon atom and the general formula .1: number of carbon atoms, said 'carboxylic acid having a minimum of 8 carbon atoms and having wherein m, y, and z are equal and R is a hydroxyl substituted aliphatic hydrocarbon radical having not more than one olefinic double bond;

14.- The composition of claim 1 in which the ester is a saturated compound. I

15. The composition of claim 1 in which the ester is derived from a carboxvlic acid having from 12 to 24 carbon atoms.

FULTON L. JOHNSTON. 

